The continued increase in world population has accentuated the demand for ingredients suitable for human food and animal feed. It is well known that carbohydrates, proteins and fats are the main ingredients in any food or feed composition.
Due to the nature of oils and fats they are not easy to handle and incorporate in the formulation during manufacture. Furthermore there may be a stability problem during storage due to coalescence and oxidation. Consequently, there is a demand for fat-containing ingredients that facilitate handling and at the same time possess high stability. Some prior art compositions comprising proteins and oils and fats in disperse form can accomplish this. The main drawbacks of these products are that they are expensive to manufacture and generally have a content of substances that do not add to the nutritional value.
This demonstrates the need for a new type of product that is less expensive to manufacture, which at the same time is nutritionally optimized and has good functional properties and possesses high stability on storage as well as in the final formulation.
The film-forming ability of several proteinaceous substances and their use as edible coatings are known in the art. The film is normally formed by casting or upon solvent evaporation from the surface of a solution. Reference is made to Edible Coatings and Films to Improve Food Quality, Chapter 9, p. 201-223; Technomic Publishing Co. Inc., 1994.
WO 2004/009054 discloses a method for encapsulating an encapsulant comprising admixing an oil component which comprises an encapsulant, with an aqueous component, and a film-forming component to form an emulsion, subjecting the emulsion to homogenization to obtain an oil-in-water emulsion comprising oil droplets wherein the oil droplets comprise the encapsulant and have a diameter of less than about 50 μm, and the film-forming component forms a film around the oil droplets and encapsulates said encapsulant, and applying a protective coating on the film-coated droplets to obtain pellets and to prevent diffusion of said oil component to the surface of the pellets. The protective coating comprises at least one member selected from the group consisting of an aqueous corn protein solution, a denatured whey protein solution, a film-forming starch solution, and an alginate. If the film-forming component is a protein it is preferred that the protein is denatured. WO 2004/009054 does not disclose the possibility of encapsulation of an oil component without the final protective coating.
Another way of increasing the encapsulating potential of proteinaceous substances is to form Maillard reaction products between amino acid groups in the proteins and reducing sugars. WO 2001/074175 discloses a method for encapsulation of oxygen sensitive oils or oils containing oxygen sensitive substances in proteins, which have been reacted with carbohydrates containing reducing sugar groups. An aqueous mixture of a protein, preferably casein, and a carbohydrate, preferably a sugar, is heated to within the range of 60 to 160° C. so that Maillard reaction products are formed in the aqueous mixture. The oil phase, up to 50% by weight is then emulsified with the aqueous phase to form microencapsulated particles. The formation of Maillard reaction products may also be done after emulsification prior to drying. The emulsions can be used as food ingredients, optionally after drying to form powders.
Formation of generally insoluble protein polymers by a catalytic cross-linking reaction can also increase the encapsulating potential of proteinaceous substances. JP 2001078718 discloses a method for the production of an active ingredient useful for food, feed, etc., in which the use of an aldehyde as a cross-linking agent is avoided by carrying out an atomization of a cross-linkable protein, a transglutaminase and the active ingredient. The cross-linkable protein is selected from the group consisting of gelatin, casein, soya bean proteins, corn proteins and collagen and is completely mixed with a transglutaminase derived from a microorganism and an aqueous solution of an active ingredient such as a vitamin, a human food additive or an animal feed additive. An atomization of the resultant mixture is then carried out in an inert gas atmosphere loaded with hydrophobic silica, cornstarch or a hydrophobic cornstarch to produce an active ingredient preparation. Subsequent to the atomization the resultant preparation is preferably further dried until the residual moisture content is below 10% by weight.
The most common way of manufacturing powdered fat compositions is by forming an emulsion that comprises water, the fat, proteinaceous substances and an emulsifier. The powdered composition is obtained by drying the emulsion by a suitable process, e.g. spray drying. GB 822614 discloses a free-flowing fatty powder comprising a dried emulsion of a fat and a partial ester of a glycol with a saturated higher fatty acid encapsulated in a hydrophilic solid or in a mixture of such a solid and a sugar or other carbohydrate. The hydrophilic solid is exemplified by dried fat-free milk, whey and butter milk, sodium caseinate, soya protein derivative, gelatin, hydrolyzed fish protein, egg albumen, dried whole egg or egg yolk, cellulose ethers, pectins, alginates, gum arabic, gum tragacanth. Furthermore, a method for the production of the free-flowing fatty powder is disclosed. The method comprises melting the fat together with said partial ester, and with lecithin, if used, emulsifying the melted mixture in a solution of the encapsulating solids, or a mixture of these solids and sugars or other carbohydrates, and then effecting spray drying.
GB 937564 discloses a powdered fat composition and a method of making a water dispersible, water-stable, powdered fat, said method comprising the steps of blending an edible oil together with a film-forming composition comprising a hydrophilic protein and a quantity of water sufficient to hydrate and disperse said protein but not in excess thereof, agitating the blend thus formed to convert the same into a physically bound dispersion consisting of a continuous encapsulating phase comprised of said film-forming composition, and an internal encapsulated phase comprised of said edible oil, and drying said encapsulating phase. Preferred protein comprises fresh egg whites and reconstituted egg white solids.
One objective of the invention is to provide a simple and inexpensive method for the manufacture of a composition comprising proteins and disperse fats. Another objective is that the products produced by the invented method are easy to handle and at the same time possess high stability towards coalescence and oxidation during storage.
Yet a further objective is that the products at the same time have a high nutritional value.